1. Field of the Invention
The present invention relates to a coater apparatus for coating a web of paper. More specifically, the present invention relates to a coater apparatus having a coater and a single tier coating dryer group disposed downstream relative to the coater.
2. Information Disclosure Statement
With the introduction of the Total BelRun dryer arrangement, which became operational in Leykam, Austria, in 1989, the speed at which the web could be dried was greatly increased.
More specifically, the Total BelRun dryer section arrangement includes a plurality of single-tier drying groups with each successive group drying an alternate side of the web. Furthermore, the web is transferred between adjacent groups without open draw and the web proceeds through the drying section while being restrained against cross-machine directional shrinkage, thereby inhibiting cockle and curl of the resultant dried web.
Dryer sections located after coaters in the prior art utilize dryer sections with a series of open draws. The web in these open draws is susceptible to sheet flutter, cross-machine directional shrinkage, cockle and curl. The aforementioned problems are similar to the problems experienced in the open draw dryer sections of conventional main dryer groups which utilize two tier dryer arrangements.
In many applications, it is necessary to coat the dried web as a continuous operation. Although off-line coaters have been proposed in which the dried web is calendered and wound in preparation for subsequent batch mode coating, the present invention provides an on-line or constant run coater of compact configuration which permits coating of one or both sides of the dried, calendered web prior to final winding thereof.
More specifically, although on-line coaters have been previously used in the manufacture of coater papers, Applicant is unaware of an on-line or constant run coater apparatus which includes a single-tier coating dryer group disposed downstream relative to the coater.
A constant run coater otherwise known as an on-machine or on-line coater apparatus of the aforementioned type is described at column 1, lines 20-40, in U.S. Pat. No. 4,728,396 to R. J. Alheid by way of contrast to the off-line coater claimed in U.S. Pat. No. 4,728,396.
Therefore, it is a primary object of the present invention to provide an on-line or constant run coater apparatus for coating a web of paper that overcomes the aforementioned inadequacies of the prior art designs and which provides a coater apparatus of compact dimensions, thereby reducing the cost of manufacture thereof.
Another object of the present invention is the provision of an on-line coater apparatus which includes a tail cutter disposed upstream relative to a calender so that a downstream coater can be threaded on-line.
Another object of the present invention is the provision of an on-line coater which includes a single-tier coating dryer group which is disposed downstream relative to a coater for drying one side of the web, the apparatus also including a further single-tier coating dryer group disposed downstream relative to the single-tier coating dryer group such that the web extends in open draw therebetween, thereby permitting a further tail to be cut from the web for subsequent threading through a further coater.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description taken in conjunction with the annexed drawings.